Time-dependent evaluation of the textural and rheological properties of psyllium-based rafts : A dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Food Innovation at Lincoln University

Abstract

Gastroesophageal reflux disease (GERD) is a gastrointestinal condition that affects many patients, who are often treated with antacid medications containing sodium alginate and exhibiting raft-forming properties. The clinical effectiveness of alginate-based systems exists; however, these systems have three main drawbacks, which include high sodium content, inflexible formulation structure, and their need for particular ionic environments to function. The study investigates Plantago ovata psyllium husk as a potential sodium alginate replacement for raft formation because of its gelation properties and its ability to preserve structure and viscoelastic properties under gastric simulation conditions. The compounds calcium carbonate and sodium bicarbonate were used as gas-generating and crosslinking agents to develop psyllium husk-based formulations which they combined with MCC and calcium caseinate for formulation adjustment. The control formulation used sodium alginate as its main ingredient. The visual stability tests were performed to study raft formation during 1, 2 and 3 hour periods in simulated gastric fluid. The Fourier-transform infrared spectroscopy (FTIR) was used to study both structural and molecular interactions during the first 30 minutes and the subsequent 2 hours. Texture Profile Analysis (TPA) was used to measure firmness, consistency, and cohesiveness and work of cohesion. The amplitude and frequency sweep tests were used to evaluate gel strength and network development over time and viscoelastic behavior through G′ vs G″ measurements. The results demonstrated that psyllium husk-based systems formed stable rafts which demonstrated or exceeded the bonding strength of alginate control systems. The combination of MCC with calcium caseinate in formulations produced stronger products which maintained better storage modulus values and showed improved structural stability through two hours of incubation. The FTIR analysis results revealed that the network structure became stronger because hydrogen bonding and polysaccharide–protein interactions functioned together. The research data shows that psyllium husk serves as an effective fiber-based substitute for sodium alginate to create raft-forming antacids which provide GERD patients with additional health benefits. Future studies could focus on optimising psyllium-husk-based formulas via various controlled clinical trials and scaled-up rheological validation for establishing dosage standardisation, commercial feasibility, and a long-term, efficient product as an alternative to sodium alginate in GERD management.